Gear changing mechanism



Sept. 7, 1954 C. M. HATH AWAY GEAR CHANGING MECHANISM Filed Feb. 27, 1951 Mew/ Patented Sept. 7, 1954 GEAR CHANGING MECHANISM Claude M. Hathaway, Denver, 0010., assignorto Hathaway Instrument Company, Denver, 0010., a corporation of Colorado Application February 27, 1951, Serial No. 212,879

2 Claims. 1

The present invention relates to a gear changing mechanism particularly adapted for recording apparatus, including oscillographs.

In making records with an oscillograph, it is desired to move the record receiving material at different rates of speed. This record receiving material may be film or photosensitive paper. In the past, arrangements have been provided employing a plurality of pulleys of different size and a belt which could be shifted to provide a small number of different speeds. Such arrangements, however, are inconvenient and oftentimes the looseness of the belt might not permit the desired steady operation. It, therefore, would be desirable to provide a more reliable means for obtaining different operating speeds of the record receiving material and also an arrangement which would be easier to adjust.

In accordance with the present invention it is contemplated to provide a gear changing mechanism having a plurality of knobs or levers which can be shifted to provide a different speed ratio without any further manipulation or the use of clutch mechanisms.

It therefore is an object of the present invention to provide an improved gear changing mechanism particularly suited for recording apparatus.

Other and further objects of the present invention subsequently will become apparent by reference to the following description taken in conjunction with the accompanying drawing wherein:

Figure l is a plan view of the gear changing mechanism with a portion of the cover or casing broken away;

Figure 2 is a side view of the gear changing mechanism with a portion of the cover broken away; and

Figure 3 is an end view of the gear changing mechanism.

In the drawing there is shown a gear changing mechanism having a housing or casing provided with a removable cover |2 held in position by suitable fastening means such as screws I3. On the outside of the casing N there is mounted a driving pulley l4 connected to a driving shaft I5. A belt tightening or idler pulley I3 is mounted on a spring biased pivoted lever H. A driven shaft I8 is provided with a driven pulley or wheel I 9.

On the front cover |2 there is found a knob 2| which is connected to a lever 22. The knob 2| is reciprocable in the lever 22 so that a reduced diameter portion thereof extending beyond lever 22 may engage a selected one of a number of apertures 23 provided in an auxiliary plate 24, which is secured to the cover |2 by a plurality of rivets 25. The lever 22 is pivotally mounted so as to be coaxial with an idler gear shaft 26 which is fixed in a boss 21 on one side of the casing and is held in position by a nut 28.

The front of the cover I2 also has another knob 29 connected to a lever 3| pivoted coaxially with the driving shaft l5.

The lever 22 is connected by a suitable sleeve arrangement on the idler shaft 28 to a plate 32 which carries a plurality of gears. In theconstruction shown in Figure 1 a pair of plates 32 is provided to support three gears 33, 34 and 35,

each of which is in engagement with an idler gear 36. The gear 33 is secured to a smaller gear 3'! adapted to engage a driven gear 38 mounted on the shaft IS. The gear 34 may be moved to directly engage the gear 33. The gear 35 is connected to another gear 39 which is arranged to be moved into engagement with the gear 38.

The lever 3| is connected to a pivoted plate or plates 4| which support a plurality of gears 42 and 43, each in engagement with a gear 44 connected to the driving shaft l5. The gear 42 is so arranged as to engage directly the idler gear 36. The gear 43 is connected to a gear 45 which may be moved into engagement with the idler gear 36.

The lever 3| in the position shown in Figure 2 provides a high gear ratio between the driven shaft and the idler shaft, and a low gear ratio when moved to the other position where the knob 29 engages an aperture 46 in the plate 24.

The lever 22 in the position shown in Figure 2 provides an intermediategear ratio between the idler gear 36 and the driven gear 38. In the other extreme position a low gear ratio is obtained when the gear 39 is in engagement with the gear 38. When the gear 34 is in engagement with the gear 38 the lever 22 is in the intermediate position and provides the highest speed of operation.

Thus in one embodiment with the lever 3| in the position shown in Figure 2 a movement of the lever 22 to positions A, B and C, respectively, will provide speeds of 1, 4 and 2 inches per second. With the lever 3| moved to the position D the lever 22 in positions A, B and C will provide respectively speeds of 3, 12 and 6 inches per second.

Since no massive loads are encountered in the use of a device of this kind, it is possible to shift gears in order to change speed without the use 3 of any clutch device. The shifting from one speed to another is done so easily that in general the operator is not aware of the fact that gears have been shifted.

From the foregoing it will be noted that the driving shaft i5 is provided with a plate which is shiftable to a plurality of positions. This plate carries a plurality of gears, each having their medial tooth lines arranged in a common are so that a common are passes through the tooth lines of gears 42 and 45. Similarly, the plate 32 carries a plurality of gears 31, 34 and 39, each having their medial tooth lines tangent to a common arc, which are is tangent to" the medial tooth line of the gear 38. By providing such arrangement whereby a plurality of gears have their medial tooth lines tangent to a common are, which in turn is common to a tooth line of a gear to be engaged, it is possible to provide a simple gear changing mechanism which is readily adjusted without difficulty and which is surprisingly smooth in its operation.

While for the purpose of illustrating and describing the present invention a particular embodiment has been shown in the drawing, it is to be understood that such other embodiments including variations therein are contemplated as may be commensurate with the spirit and scope of the invention defined in the accompanying claims.

I claim as my invention:

1. A gear changing mechanism comprising an input shaft and an output shaft each carrying. a gear fixed thereto, one of said shafts pivotally supporting a plate carrying two gears having their medial tooth lines arranged tangent to a common are about the axis of said shaft, one of said gears being connected directly to the gear on said shaft and another of said gears being connected to a coaxial gear which engages the gear on said shaft, an idler gear mounted on a shaft arranged intermediate said shafts and having its medial tooth line tangent to said common are, a second plate pivotally mounted on one of said remaining shafts and carrying at least two gears having their medial tooth lines arranged tangent to a common are which is tangent to the medial tooth line of the gear on the remaining shaft, one of said gears being connected directly to the gear on the shaft supporting said latter plate and another of said gears being connected by coaxial reduction gear means to the gear on the shaft supporting said latter plate, and means for shifting and retaining said plates in selected positions to change the gear ratio between said input shaft and said output shaft.

2. A gear changing mechanism comprising a driving gear, an idler gear spaced therefrom, a support plate pivotally mounted on the axis of said driving gear, said plate carrying two gears having their medial tooth lines arranged tangent to a common are for selective engagement with said idler gear, at least one of said gears on said plate being connected through a coaxial reduction gear to said driving gear, a driven gear spaced from said idler gear, a second plate pivotally mounted on the axis of one of said remaining gears, three gears mounted on said second plate having their medial tooth lines arranged tangent to a common are which is tangent to the medial tooth line of the remaining gear, two of said gears on said latter plate each being connected to its own coaxial reduction gear which engages the gear on the axis of said plate, and means for manually shifting the positions of said plates andlatching said plates in position to predetermine the gear ratio between said driving gear and said driven gear.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 780,642 Earl Jan. 24, 1905 922,880 Garvin May 25, 1909 2,285,743 Musselman June 9, 1942 

